1K4D

Potassium Channel KcsA-Fab complex in low concentration of K+

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.218 

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This is version 1.4 of the entry. See complete history. 


Literature

Chemistry of ion coordination and hydration revealed by a K+ channel-Fab complex at 2.0 A resolution.

Zhou, Y., Morais-Cabral, J.H., Kaufman, A., MacKinnon, R.

(2001) Nature 414: 43-48

  • DOI: 10.1038/35102009
  • Primary Citation of Related Structures:  
    1K4C, 1K4D

  • PubMed Abstract: 

    • Ion transport proteins must remove an ion's hydration shell to coordinate the ion selectively on the basis of its size and charge. To discover how the K+ channel solves this fundamental aspect of ion conduction, we solved the structure of the KcsA K+ channel in complex with a monoclonal Fab antibody fragment at 2 ...

    Ion transport proteins must remove an ion's hydration shell to coordinate the ion selectively on the basis of its size and charge. To discover how the K+ channel solves this fundamental aspect of ion conduction, we solved the structure of the KcsA K+ channel in complex with a monoclonal Fab antibody fragment at 2.0 A resolution. Here we show how the K+ channel displaces water molecules around an ion at its extracellular entryway, and how it holds a K+ ion in a square antiprism of water molecules in a cavity near its intracellular entryway. Carbonyl oxygen atoms within the selectivity filter form a very similar square antiprism around each K+ binding site, as if to mimic the waters of hydration. The selectivity filter changes its ion coordination structure in low K+ solutions. This structural change is crucial to the operation of the selectivity filter in the cellular context, where the K+ ion concentration near the selectivity filter varies in response to channel gating.

    Organizational Affiliation: 

    Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, Connecticut 06520, USA.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
antibody Fab fragment heavy chainA219Mus musculusMutation(s): 0 
Gene Names: Ighg1, Igh-4
UniProt
Find proteins for P01868 (Mus musculus)
Explore P01868 
Go to UniProtKB:  P01868
Entity Groups  
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UniProt GroupP01868
Protein Feature View
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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
antibody Fab fragment light chainB212Mus musculusMutation(s): 0 
Gene Names: Igkc
UniProt
Find proteins for P01837 (Mus musculus)
Explore P01837 
Go to UniProtKB:  P01837
Entity Groups  
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UniProt GroupP01837
Protein Feature View
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Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
potassium channel KcsAC124Streptomyces lividansMutation(s): 2 
Gene Names: kcsA, skc1
Membrane Entity: Yes 
UniProt
Find proteins for P0A334 (Streptomyces lividans)
Explore P0A334 
Go to UniProtKB:  P0A334
Entity Groups  
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UniProt GroupP0A334
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
DGA
Query on DGA
Download Ideal Coordinates CCD File 
G [auth C]DIACYL GLYCEROL
C39 H76 O5
UHUSDOQQWJGJQS-QNGWXLTQSA-N		 Ligand Interaction
F09
Query on F09
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H [auth C]NONAN-1-OL
C9 H20 O
ZWRUINPWMLAQRD-UHFFFAOYSA-N		 Ligand Interaction
K
Query on K
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D [auth C],
E [auth C]		POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N		 Ligand Interaction
NA
Query on NA
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F [auth C]SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N		 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.218 
  • Space Group: I 4
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 155.29α = 90
b = 155.29β = 90
c = 75.74γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
AMoREphasing
CNSrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-11-14
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2011-11-16
    Changes: Atomic model
  • Version 1.4: 2021-10-27
    Changes: Database references, Derived calculations